4.3l Not turning off

[tahoejag]

Turning the key off...engine still continues to run. ????? Have to use the kill switch or the master power button to shut engine off. Replaced ignition switch aprx 2 years ago. Never experienced this before. Advice/ideas?.....thank you in advance.

 

[harringtondav]

Does the engine continue to idle normally, or does it sputter and surge? If the first, it sounds like an electrical problem. Most boat's wiring leaves B+ available for the blower, radio, lights, bilge pump, etc. in key 'off'. Make sure you don't have your 'run' circuit tied into these. With the key off, you should have zero voltage between the '+' coil terminal and the loose '+' wire. If there is 12V, you need to recheck your ign. switch wiring.

If it sputters/surges the engine is running on due to several causes.: Hot carbon build up on the exhaust valves or plugs. Mine did this until I tweaked over-rich idle mixture screws more to the lean setting.

 

[Rick Stephens]

I'd take a test light to the ignition switch. Doesn't matter if it was just replaced 2 years ago. Make sure it actually disconnects power when switched off. Could also be something as not obvious as the wire terminals twisting and contacting each other on the back of the switch.

 

[tpenfield]

+1 for testing the ignition switch.

 

[alldodge]

Seeing this is a TKS its probably the diode shorted out